The invention relates to milking claws and more particularly the top unloading type.
Top unloading milking claws are known in the prior art, and include a lower bowl, an upper top closing the bowl, and a vertical riser outlet tube extending from the top downwardly into the bowl. The outlet tube is connected to a vacuum source for drawing milk from the bowl. The lower end of the outlet tube is adjacent the bottom of the bowl and spaced therefrom by a small space through which milk flows from the bowl into the outlet tube. Milk is forced into the outlet tube by the pressure differential between the air within the claw above the surface of the milk and the vacuum within the outlet tube, which pressure differential acts across and upon the surface of the milk within the bowl.
In some claws, inlets in the top direct incoming milk flow tangentially along the inner surface of the bowl. The milk swirls around the bowl and is pushed against the outer wall by a centrifugal force component such that the milk rotates about the center of the claw at a high angular velocity. Air, which is not as dense as milk, is able to flow downwardly along the exterior of the central outlet tube to the bottom of the bowl, and then flow into the outlet tube. This detracts from the noted function of the air within the bowl, namely to provide a pressure differential to act upon the surface of the milk to force milk into the outlet tube. When the milk swirls around the bowl, and air is allowed to flow downwardly to the bottom of the bowl, the noted air pressure differential decreases, which in turn decreases milk flow capacity of the claw. Agitation of high velocity air can also cause lipolysis.